The present invention relates to an in-cylinder direct-injection engine and a cylinder head.
A typical inner wall of the cylinder head of an in-cylinder direct-injection engine has valve openings that are opened and closed with intake and exhaust valves, and an injection port for allowing fuel injected by an injector to enter the cylinder. Part of the inner wall about each valve opening forms a valve seat that contacts the corresponding valve.
The inner wall of a cylinder head disclosed in Japanese Laid-Open Patent Publication No. 6-81657 has a notch extending from an injection port. The notch prevents fuel injected from the injector from colliding with the cylinder head, that is, from interfering with the cylinder head. In the technique disclosed in the publication, the injection port is located in a part of the inner wall that is close to the periphery of the cylinder. The injector injects fuel in a direction away from the valve openings. The notch extends in a direction away from the valve openings to correspond to the injection direction.
The technique of the above publication permits a notch to be formed only for preventing injected fuel from interfering with the cylinder head. However, depending on the direction of the fuel injection, forming a notch can result in an insufficient thickness of the cylinder head at a valve seat about a valve opening adjacent to the injection port.